Study Provides New Clues to Oxytocin-Autism Connection

Oxytocin appears to partner with another vital brain chemical – serotonin – to make social contact rewarding

September 13, 2013

Stanford University researchers have shown that the so-called “love” hormone oxytocin is involved in a broader range of social interactions than previously thought.

Their new report in the journal Nature urges researchers to use the findings to open new doors in the search for autism treatments.

Because of its role in emotional bonding, oxytocin has long been of interest to autism researchers. In 2010, Autism Speaks funded the first clinical trial using oxytocin nasal spray to treat children with autism. The success of this pilot study led to government funding of a much larger clinical trial – currently in progress at centers across the country.

“Oxytocin is under intense study as a potential therapeutic intervention for autism, but we still have very little idea of how it works to affect social behavior," comments Daniel Smith, Autism Speaks senior director for discovery neuroscience.

In their new report, the Stanford researchers describe a series of technical experiments with mice that demonstrate how oxytocin influences levels of another important brain hormone – serotonin. In effect, its action was similar to that of antidepressant medicines known as serotonin-reuptake inhibitors. It increased available amounts of serotonin in the brain.

More specifically, the Stanford team showed that oxytocin increased serotonin levels in the brain’s “reward center” (nucleus accumbens). They concluded that interactions between oxytocin and serotonin may be crucial for making social interactions pleasurable.

"There are at least 14 different subtypes of serotonin receptor [in the brain]," says lead researcher Gül Dölen. "We've identified one as being important for social reward. Drugs that selectively act on this receptor aren't clinically available. But our study may encourage researchers to start looking at drugs that target it for the treatment of disorders such as autism."

Adds Smith: "By discovering a new link between oxytocin, serotonin and reward centers in the brain, Gul is connecting the dots in a way that could help identify which individuals with autism may benefit from oxytocin or related interventions.”